srcu: Make SRCU be once again optional
Commit d160a727c40e ("srcu: Make SRCU be built by default") in response
to build errors, which were caused by code that included srcu.h
despite !SRCU. However, srcutiny.o is almost 2K of code, which is not
insignificant for those attempting to run the Linux kernel on IoT devices.
This commit therefore makes SRCU be once again optional, and adjusts
srcu.h to allow error-free inclusion in !SRCU kernel builds.
Signed-off-by: Paul E. McKenney <[email protected]>
Acked-by: Nicolas Pitre <[email protected]>
diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index 4c1d5f7..ea356d8 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -62,8 +62,13 @@ int init_srcu_struct(struct srcu_struct *sp);
#include <linux/srcutree.h>
#elif defined(CONFIG_CLASSIC_SRCU)
#include <linux/srcuclassic.h>
-#else
+#elif defined(CONFIG_SRCU)
#error "Unknown SRCU implementation specified to kernel configuration"
+#else
+
+/* Dummy definition for things like notifiers. Actual use gets link error. */
+struct srcu_struct { };
+
#endif
/**
